QinGang_interested/lib/customWidget/single_images_viewer.dart

import 'dart:io';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:photo_view/photo_view.dart';
import 'package:photo_view/photo_view_gallery.dart';
import 'package:qhd_prevention/pages/my_appbar.dart';


class SingleImagesViewer extends StatefulWidget {
  final String imageUrl;
  /// 可选：多张图片列表。如果需要列表的话，imageUrl可以传空
  final List<String>? imageUrls;
  /// 可选：初始显示页（默认 0）
  final int initialIndex;

  const SingleImagesViewer({
    Key? key,
    required this.imageUrl,
    this.imageUrls,
    this.initialIndex = 0,
  }) : super(key: key);

  @override
  State<SingleImagesViewer> createState() => _SingleImagesViewerState();
}

class _SingleImagesViewerState extends State<SingleImagesViewer> {
  late final List<String> _urls;
  late final PageController _pageController;
  int _currentIndex = 0;

  @override
  void initState() {
    super.initState();
    // 优先使用 imageUrls
    if (widget.imageUrls != null && widget.imageUrls!.isNotEmpty) {
      _urls = widget.imageUrls!;
    } else {
      _urls = [widget.imageUrl];
    }

    _currentIndex = (widget.initialIndex >= 0 && widget.initialIndex < _urls.length)
        ? widget.initialIndex
        : 0;
    _pageController = PageController(initialPage: _currentIndex);
  }

  ImageProvider _providerFromUrl(String imageUrl) {
    final lower = imageUrl.toLowerCase();
    if (lower.startsWith('http')) {
      return NetworkImage(imageUrl);
    } else if (imageUrl.startsWith('assets/') ||
        imageUrl.startsWith('package:') ||
        imageUrl.startsWith('packages/')) {
      return AssetImage(imageUrl);
    } else {
      if (!kIsWeb) {
        try {
          final file = File(imageUrl);
          if (file.existsSync()) {
            return FileImage(file);
          } else {
            return AssetImage(imageUrl);
          }
        } catch (e) {
          return AssetImage(imageUrl);
        }
      } else {
        return AssetImage(imageUrl);
      }
    }
  }

  @override
  void dispose() {
    _pageController.dispose();
    super.dispose();
  }

  Color _bgColor() => Colors.black.withOpacity(0.9);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: _bgColor(),
      appBar: MyAppbar(
        isBack: false,
        actions: [
          IconButton(
            onPressed: () => Navigator.of(context).pop(),
            icon: const Icon(
              Icons.close,
              color: Colors.white,
              size: 40,
            ),
          ),
        ],
        backgroundColor: _bgColor(),
        title: '',
      ),
      body: Stack(
        children: [
          PhotoViewGallery.builder(
            pageController: _pageController,
            itemCount: _urls.length,
            onPageChanged: (index) => setState(() => _currentIndex = index),
            builder: (context, index) {
              final url = _urls[index];
              return PhotoViewGalleryPageOptions(
                imageProvider: _providerFromUrl(url),
                minScale: PhotoViewComputedScale.contained,
                maxScale: PhotoViewComputedScale.covered * 2,
                onTapUp: (context, details, controllerValue) {
                  Navigator.of(context).pop();
                },
              );
            },
            backgroundDecoration: BoxDecoration(color: _bgColor()),
            // enableRotation: false, // 如果需要可打开旋转
            loadingBuilder: (context, progress) => const Center(
              child: CircularProgressIndicator(),
            ),
          ),

          // 页码指示
          if (_urls.length > 1)
            Positioned(
              right: 12,
              top: 12 + MediaQuery.of(context).padding.top,
              child: Container(
                padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
                decoration: BoxDecoration(
                  color: Colors.black.withOpacity(0.45),
                  borderRadius: BorderRadius.circular(16),
                ),
                child: Text(
                  '${_currentIndex + 1} / ${_urls.length}',
                  style: const TextStyle(color: Colors.white, fontSize: 14),
                ),
              ),
            ),
        ],
      ),
    );
  }
}